When I wrote about busy speakers recently, from the perspective of an event organiser, I was also writing about myself a little bit, since I've been one of those "busy" speakers on more than one occasion. So I know why you'll sometimes end up in such a situation.
It's usually one of the following:
"I've given this presentation before"
But a presentation always needs some adjustments for the target audience and the circumstances. You may think that the audience at conference B is similar to that of conference A, where you gave the presentation before. I'll bet that you will find differences, though, if you'll look closely. No two audiences are exactly the same. And sometimes, depending on your topic, the simple fact that some time has passed since you last gave that talk can make all the difference.
Adjusting a talk for a new audience can be as simple as replacing the opening slide and introduction - or it can require you to completely take apart the presentation.
For example, I was once asked to give a presentation again to another audience. I had less time and the target audience was different - software testers instead of software developers. My talk had 3 parts and one of them was really only of interest to software developers, so I cut it out. Problem solved? Not at all. When I rehearsed the talk, I noticed that the 3 parts weren't as independent as I thought they were and that I now had some jumps and holes in my presentation. I ended up taking the entire presentation apart and putting it back together in a different way, adding some new content as well. Pretty much the only part that survived was the introduction.
Never underestimate the amount of work that a presentation may require, even if you think you can simply pull out a talk that you gave before.
Presentation-driven Development or Presentation-driven Research
Laura Thomson used the term "presentation-driven development" in her talk at DC4D, "Public speaking for Developers". What she means by this is that sometimes you are tempted to submit a presentation to a conference that you haven't completely thought through yet. But since you're working on the topic at the moment anyway and the event is seemingly far away in the future, it seems like a safe bet that you will have "something interesting" to talk about by that time.
Unsurprisingly, this often doesn't work out. Your work may be rescheduled, other things may come up or you're simply so busy with your work that you don't have the time to prepare the findings for a presentation.
I'm guilty of a variant of this, which I'd call presentation-driven research: I had all the necessary data available (or thought I would have it in time) and I "only" had to draw the conclusions. Guess what? It didn't work out. The result was a pretty weak and vague talk - not at all what the audience expected after seeing the title. And of course they noticed and were disappointed.
A hint that you're working on such a presentation is when your talk's title isn't making a statement. You don't know the outcomes of your development or research yet, so you end up with a generic title along the lines of "Lessons learned from ...". If you really had learned a lesson, you would be able to come up with a much stronger title, stating that lesson.
Don't be that busy speaker. Only submit a talk when you know you can deliver. And don't underestimate the amount of work that may go into updating an existing talk for a new audience.
(Image credits: Busy Businessman 3 by Piotr Bizior, from stock.xchng)
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